Elongate Vacuum System for Coating One or Both Sides of a Flat Substrate

ABSTRACT

An elongate vacuum system for coating one or both sides of a flat substrate which can be displaced by the system, comprises at least one magnetron provided with a magnetron surrounding area and is subdivided into successive compartments in the direction of transportation of the substrate by separating walls having closeable suction openings. The compartments can be evacuated either directly by a vacuum connection provided on the compartment or indirectly via a suction opening in the separating wall. At least one compartment comprises an upper partial compartment which is arranged above the substrate. The partial compartment comprises a closeable upper opening in at least one of the outer walls thereof. The aim is to produce an elongate coating system which is flexible to use according to the requirements of various one and two-sided coating processes and ensures a stable, differential and process-optimized sputter atmosphere. At least in one of the upper partial compartments, horizontal and/or vertical elements can be mounted in order to subdivide the upper partial compartment into several sections.

The invention relates to an elongate vacuum system for coating one orboth sides of a flat substrate which can be moved through the vacuumsystem in a transportation plane by means of a transport system. Thevacuum system comprises at least one magnetron provided with magnetronsurrounding area and is subdivided into successive compartments in thedirection of transportation of the substrate by closeable separatingwalls comprising suction openings, which can be evacuated eitherdirectly via a vacuum connection located on the compartment orindirectly via a suction opening in the separating wall. At least onecompartment comprises an upper partial compartment which is locatedabove the substrate, the said partial compartment comprising, in atleast one of the outer walls thereof, a closeable upper opening.

A coating system which enables coating on both sides of a flat substrateduring a single conveyance of the substrate through the system isdescribed in EP 1 179 516 A1. The simultaneous arrangement of targetsabove and below the substrate moved through the system by means of atransport system enables simultaneous coating on both substrate surfaceswithin this section. At the same time, although the coating space issubdivided into several sections by barriers projecting into this, thecoating process can nevertheless only be operated in the sections withthe same or similar sputter atmosphere.

For the simultaneous operation of a coating system with processatmospheres deviating from one another considerably, the subdivision ofthe coating system into several sections to be evacuated separately aswell the separation into coating and evacuation sections is universallyknown. Such a coating system is outlined in the European patent EP 783174. It is essentially characterized by a large number of sectionslocated next to one another in the direction of substratetransportation, which together form a vacuum chamber and are connectedto one another via a passage, which forms the transportation plane forthe flat substrate. Usually, adjoining coating sections each exhibitinga cathode are separated by at least one section capable of evacuation.The side separating walls between the evacuation and coating sectionscomprise suction openings via which the adjoining coating sections areevacuated indirectly by a connected vacuum pump.

When separating two adjoining coating sections by only one evacuationsection, the vacuum pump located there consequently evacuates the,viewed in regard to the direction of transportation, previous andsubsequent coating section. As a result of this, two gas flows. Inopposite directions encounter each other in the evacuation section,which leads to turbulence and has a deleterious effect on the evacuationprocess and the performance values of the vacuum pump.

If the various coating sections are operated with different sputteratmospheres, further sections connected to the vacuum pump are necessarybeside the evacuation section, which serve as pressure stages or for thegas separation. In this case, the coating system is elongated by theadditionally required section, which leads to very longitudinallyextended systems with large evacuation volumes when locating next to oneanother several different sputter atmospheres, sputter powers and/orcathode materials.

In a further development of the system, which is described in the patentspecification DE 197 33 940, the evacuation sections are shortened incomparison to the coating sections and separated in the center by atransverse bulkhead arranged transverse to the direction oftransportation, so that the vacuum pumps located in a series above thetransverse bulkhead evacuate either the previous or the subsequentcoating section by means of suitable recesses in the transverse bulkheadand corresponding to positioned baffle plates, depending on theadjustment of the baffle plate. This asymmetrical (as alternate)allocation of the pumps through the adjustment of the baffle plate leadsto a pressure gradient and hence to deviations in the sputter conditionswithin the adjoining, indirectly evacuated coating section.

In this arrangement as well, a coating section usually follows anevacuation section, whereby both sections exhibit different dimensions.Correspondingly, an opening with different dimensions for each sectiontype is incorporated in the upper wall of each section, which holdseither a vacuum pump or a cover. A cathode removal with each coverincluding its cathode surroundings, comprising screens and media feedand extraction, can be mounted on each cover. At the same time, itproves to be very advantageous that the sequence of the sections cannotbe changed on account of their different sizes for each coating system.

The cathode and its cathode environment is omitted in at least onecoating section which is located between the coating sections to beseparated and their adjoining evacuation sections in order to realize agas separation for operating the system with different sputterconditions. In addition to this, the baffle plates are placed in theadjoining evacuation sections in such a way that both pumps evacuate theseparation section located between this. As a result of this, andbecause, as described, only every second one of the next pumps seriesbut one evacuates the coating sections coming before or after the gasseparation, the pump power is significantly reduced in the coatingsections located next to the gas separation, which leads to deviationsin the sputter conditions between the sections.

The invention therefore has the task of providing an elongate coatingsystem which is to be designed flexibly for the requirements ofdifferent one and two-sided coating processes in respect to the processcycle through within the system and which thereby ensures a stable,differentiable and process-optimized sputter atmosphere.

The task is solved in the sense of the invention in such a way that atleast horizontal and/or vertical elements can be mounted in one of theupper partial compartments for subdividing the upper partialcompartments into several sections.

Corresponding to the present invention, the partial compartments exhibitno fixed conditioning for one of the possible functions as a coating,evacuation or gas separation section. Rather, the equipping of eachpartial compartment is enabled for one of these functions variablywithin a single system through the assembly or disassembly of thehorizontal and vertical elements possible in particular via theclosable, upper openings, without a cost and time-intensive complexconversion of the system.

The task underlying the invention in respect to the flexible designoptions of a vacuum system due to the horizontal and vertical elementsdescribed being capable of disassembly is meet to a particular degree,as the user himself can adapt not only the corresponding equipment andcorresponding closure of the openings, but also a single system to hischanging technological requirements through variable separation ofsections.

At the same time, the sequence of the process sections following oneanother is almost freely selectable corresponding to the requirements ofthe planned coating result, without being fixed by circumstancesassociated with the system. In this way, in particular pump and gasseparation sections can be added to a certain extent through variablesubdivision of the partial compartments into, for example, two sections.

This variable subdivision is particularly advantageous as it satisfiesthe aspect of the stable, differentiable and process-optimized sputteratmosphere. In this way, for example, only one of the two adjoiningsections is therefore evacuated by closing the suction openings of aseparating wall. Amongst other things, a reduction in the suction powerof the vacuum pump is prevented, which would otherwise result throughthe two gas flows encountering each other and swirling out of thepartial compartments opposite one another. Differentiable processatmospheres and coating of specific sections within the compartment isalso possible and can be maintained with stability, which corresponds toan essential aspect of the task in the sense of the present invention.

Corresponding to a particularly favorable embodiment of the invention,it is envisaged that at least a further lower compartment limited by theseparating walls is located below the transportation plane, which in atleast one of the outer walls exhibits a closable lower opening as wellas a closable suction opening in each separating wall.

The flat substrate moved through the system separates the space abovethe transportation plane from the space below the transportation planein each section, whereby the transportation plane is the plane in whichthe substrate is moved. For the purpose of coating the substrate on bothsides, a coating space below the transportation plane can thereby bedefined. Through the fact that both space sections resulting in thisway—in particular if they also exhibit horizontal and/or verticalelements that can be mounted corresponding to a further design of theinvention—are to be designed so as to be variable in a comparative wayas the upper partial compartments, a stable, differentiable andprocess-optimized sputter atmosphere as well as variable coatingparameters can be produced for the underside coating in the mannerrepresented.

Consequently, either vacuum pumps can be connected to the lower partialcompartments independently of the equipment of the upper partialcompartment located above the substrate, or are equipped with at leastone magnetron, whereby the space below the substrate of a sectionequipped in this way is useful for evacuation of the vacuum system orfor underside and hence two-sided coating in a cycle through.

In the standard fitting, it proves to be very practical if themagnetrons including the magnetron surrounding area are mounted throughthe openings in the upper and/or lower outer walls, and the vacuumconnections are located in the openings of the side outer walls.However, it is also possible to replace this assignment of the openingscompletely or for individual partial compartments, with the result thatthe magnetrons can be mounted on the sides of the vacuum system.

It proves to be especially advantageous if definite sections of thecoating system, viewed from the aspect of the transportation direction,are fitted both above and below the transportation plane for a definitefunction or at least comparable functions, for example gas separation,whereby the lower partial compartment exhibits the same or at least asimilar arrangement of the horizontal and/or vertical elements as theupper partial compartment opposite it above the transportation plane.

Through the fact that the upper and lower openings, irrespective ofwhether they are located in the upper or respectively the lower outerwall or in a side outer wall, can be closed with covers and at least onemagnetron including the magnetron surrounding area can be mounted on acover, and/or a vacuum connection is in place or a cover can only serveas a closure, it is possible to convert a single system for the mostdiverse coating configurations. This advantage is extended yet furtherif, corresponding to a further embodiment of the invention, the coversexhibit the same dimensions in respect to each other and can thereforeby replaced by one another. In this way, it is easy to change theequipment of the individual partial compartments by replacing thecovers.

A variable vacuum chamber of this type makes it possible, through thesuitable arrangement of the vacuum connections, magnetrons and closingcovers as well through the corresponding choice of coating parameters orseparation of the sections of different coating conditions and through asuitable transport system, to realize a coating process with which thesubstrate underside can be coated at the same time as and independentlyof the substrate upper side.

The replaceability and the uniform size of the covers, however, does notnecessarily require a uniform size of the openings themselves. Openingsof various designs can also be closed with covers of the same dimensionsthrough an effective embodiment not described in more detail here withadapters.

On the other hand, if the upper openings of all partial compartmentsexhibit the same dimensions, as is envisaged in a specially equippedversion of the invention, the covers including the mounted componentscan be replaced with each other without further conversions, whichfurther increases the variability of the coating system corresponding tothe task of the invention.

In the same way, it remains free, in the sense of the high level ofuniversality of the vacuum system corresponding to the invention,whether special covers are provided for the connection of one or morevacuum pumps, one or more magnetrons or only for closure of the opening,or whether a universal cover version enables all three application formsthrough corresponding add-ons or conversions.

Insofar as the width of the vacuum system and the size of the openingspermit it, the arrangement of several vacuum pumps or their connectionsin the openings of the upper and lower outer walls is possible in asequence vertical to the direction of transportation. Whether severalconnections located in a row are supported by several or by only onecover, depends on the size of the system and the spatial requirementnecessary for the connections.

Another embodiment corresponding to the invention envisages that atleast a side outer wall of an upper and/or lower partial compartmentexhibits a vacuum pump. This enables a comparatively variable system,even if, for example, the constructional circumstances do not permit anequipping of the system with magnetrons or vacuum pump connections onthe lower side of the system. In this case, the evacuation of thepartial compartment or sections can be realized via the side vacuum pumpconnections and the underside coating can, for example, be realized viaa magnetron suspended in a certain way from a cover of an upper openingbelow the substrate.

It is also possible to close the upper openings, corresponding to theconstructional circumstances and the possible technologicalrequirements. In particular, the free space in front of the respectiveouter wall available for operation and maintenance is considered as aconstructional opportunity.

An especially advantageous embodiment envisages that the elements forthe horizontal and for vertical subdivision of the partial compartmentare even. This is because, in particular in this case, it is possiblethat at least one horizontal element is located on holding devicesexhibiting a horizontal supporting surface, which are present on at lasttwo opposite walls of the partial compartment, the side outer wallsand/or the separating walls. Owing to the pressure ratios in the vacuumsystem, no special sealing systems are necessary for the subdivision ofa partial compartment into sections in the sense of the presentinvention.

The usual technical fitting accuracies of the horizontal element to thesurrounding walls and its loose location on the holders is sufficientfor the effective subdivision in respect to the outlined possiblefunctions of the sections in the case of coating parameters of theadjoining sections which do not deviate form one another toosignificantly. The fixing in this version is solely by the weight of thehorizontal element.

It is easy to see that the conversion of the system for newspecifications is very simple in this embodiment form and can berealized with the minimum of technical and time expense.

If, furthermore, at least one horizontal element exhibits, correspondingto further embodiments in the sense of the invention, a vertical elementfastened by means of a joint or by means of an insertion device, whichextends between the horizontal element and the upper or lower outerwalls directly opposite the horizontal element, the vertical subdivisionof a partial compartment equipped in this way can be realizedparticularly quickly and easily.

In a further advantageous embodiment of the invention, fixing elementsare present on the cover which closes the upper or lower opening locatedin the upper or lower outer wall opposite the horizontal element. Thesefixing elements fix the vertical element in its position after closureof the opening. This is particularly advantageous for the describedarrangement of the vertical element by means of a joint on thehorizontal element, but also otherwise enables a situation whereby thesubdivision of the partial compartment by the vertical element does notnecessarily have to occur by means of complex sealing systems, a usualfitting accuracy possibly being sufficient. In this version, thevertical element is simply fastened by putting the cover on.

Corresponding to a further advantageous embodiment in the sense of thepresent invention, the location of a gas separation is envisaged, sothat in at least one partial compartment a horizontal element is locatedin such a way that a section of the partial compartment is separated offtowards the space surrounding the transportation plane.

The separation off of this space enables the positioning of a gasseparation between two coating partial compartments operated withdifferent sputter atmospheres, whereby the transportation planeconnecting these two coating compartments is also evacuated. If thespace surrounding the transportation plane is also separated off fromthe remaining partial compartment by a horizontal element in the lowerpartial compartment located below the transportation plane, a channel iscreated in the immediate environment of the substrate, which functionsas a flow resistance and hence prevents a compensation of theatmospheres of the adjoining partial compartments. Moreover, theseparation off of the transportation space also enables divergentoperation of the pump sections separated off in this way above and belowthe substrate. Owing to the variable connection options of the vacuumpumps and magnetrons, the latter enables a situation whereby the taskscan be assumed by two coating sections, located next to one another inconventionally comparable coating systems, of partial compartmentspositioned above each other within a compartment of the systemcorresponding to the invention, hence allowing the elongation of thesystem to be reduced.

In another embodiment corresponding to the invention, it proves to beparticularly advantageous if the horizontal and/or vertical elements ofat least one partial compartment have a closeable additional suctionopening. This is always necessary in such configurations if a section isto be evacuated indirectly via the adjoining section or thetransportation plane is separated off by a horizontal element and thesection located under or above this serves as a gas separation.

A finely adjusted evacuation management is possible as an advantageousfeature, if the size of the suction openings in the separating walls ofthe compartments and/or the additional suction openings in thehorizontal and/or vertical elements are designed to be adjustable. Ifthe suction openings are designed to be automatically adjustable intheir size for example, the sputter parameters can also be optimizedduring the coating process in addition to the flexible conversion of thevacuum system in the sense of the invention.

The invention shall now be explained in more detail on the basis of anembodiment example. The associated drawing shows in

FIG. 1 the schematic representation of a longitudinal section of acoating system corresponding to the invention and

FIG. 2 a simplified longitudinal section of a section of the coatingsystem corresponding to the invention.

The elongated vacuum system shown in FIG. 1 serves for the two-sidedcoating of a flat substrate 1 in the course of a cycle through thesystem. The vacuum system consists of four evacuation compartments 2 andthree coating compartments 3, which are separated from one another byseparating walls 4. The transportation of the substrate 1 through thecoating system occurs in the transportation plane 5 by means of atransport system not represented, whereby the passages in and out of thecoating system itself as well as from one compartment into the next oneare realized via sluices 6 which are located in the separating walls 4of the compartments.

In the present embodiment example, all the partial compartments in theupper 7 as well as the lower 8 outer walls exhibit upper and loweropenings 10, 23, which can be closed tightly with covers 11 of a uniformsize. The evacuation compartments 3 also contain vacuum connections 16in the covers 11 a closing the openings in the side outer walls 9,whereby in the present embodiment example these side covers 11 a exhibita different side geometry to the cover 11 of the openings in the upper 7and lower outer walls 8. Moreover, two suction openings 12 are alsolocated in each separating wall 4 above and below the transportationplane 5 respectively. These suction openings 12 are arranged in sequenceand parallel to the substrate 1 as well as vertically to the directionof transportation 13 and can be closed tightly with a closure 14.

The first coating compartment 3 a, from the point of view of thedirection of transportation 13, comprises a magnetron 15 including themagnetron surrounding area not shown, which is located above thesubstrate 1 (sputter-down position) and is mounted on the cover 11,which closes the upper opening 10 in the upper outer wall. The firstcoating section 3 a is indirectly evacuated by vacuum pumps 16 which areconnected in the two adjoining evacuation compartments 2 on the covers11 a closing the openings in the side outer walls 9 above thetransportation plane 5. In the system configuration shown, the suctionopenings 12 in the separating walls 4 of this first coating compartment3 a are completely opened for this purpose above the transportationplane 5 and tightly closed below the transportation plane 5.

In the second coating compartment 3 b, a magnetron 15, also includingthe magnetron surrounding area not shown here, is mounted on the uppercover in such a way that a sputter-up operation is possible. For thispurpose, the magnetron 15 is positioned opposite the underside of thesubstrate 1 and the suction openings 12 located in this area of thesecond coating compartment 3 b are opened for indirect evacuation bymeans of the vacuum pumps 16 connected to the two adjoining evacuationcompartments 2. In the second coating compartment 3 b, the suctionopenings 12 above the transportation plane 5 are closed off tightly withseals 14.

The third coating compartment 3 c, on the other hand, exhibits the sameconfiguration as the second 3 b. However, the sputter atmospheres underwhich the second and third coating compartments 3 b, 3 c are operateddiffer from one another. In order to prevent a reciprocal contamination,a gas separation is provided between them. For this purpose, thetransportation plane 5 is separated off from the evacuation compartment2 by two horizontal elements 17 arranged parallel to the substrate 1above and below the transportation plane 5. While the lower horizontal17 tightly closes the partial compartment 19 located below it towardsthe transportation plane 5, the upper horizontal element 17 exhibitsfour suction openings 12 arranged in two rows, via which the separatedtransportation level 5 can be evacuated by means of vacuum pumps 16connected to a side cover 11 a of the upper partial compartment 18. Thesuction openings 12 leading into the adjoining coating compartments 3 b,3 c in the separating walls 4 of the upper partial compartment 18 aretightly closed owing to the function of the upper partial compartment 18as a gas separation.

The evacuation of the adjoining, second and third, coating compartments2 is via the same evacuation compartment 2 as the gas separation. Afurther element running vertical 20 and parallel to the separating wallsis positioned for this in the lower partial compartment 19, whichsubdivides the lower partial compartment 19 into two sections 21. Eachof the openings located in the side outer walls 9 extends over bothsections 21 and the covers 11 a closing these lower openings 23 exhibittwo vacuum pump connections 16 respectively, one in each section 21.

A further evacuation compartment 2 forms the connection of the saidvacuum system, on whose cover 11 a of the side lower openings 23 vacuumpump connections 16 are mounted. In the embodiment example described,the vacuum pumps 16 are always connected to the side outer walls 9 atthe vacuum pump connections and the lower openings 23 in the lower outerwalls 8 are only closed with covers 11 which support no furthercomponents. Likewise, it is also possible, however, to mount all orindividually selected vacuum pump connections 16 or the vacuum pumps 16themselves onto the covers 11 of the lower or upper openings 23, 10.Nevertheless, it is the special system configurations as well as themaintenance and assembly space availability which always determine ontowhich covers 11, 11 a vacuum pump connections 16 and magnetrons 15 aremounted.

FIG. 2 therefore shows a section comprising the gas separation and anadjoining coating compartment 3 with a magnetron 15 in a sputter-upposition of a vacuum pump system corresponding to the invention with asubstrate 1 moved through the system on transport rollers 22. In thisembodiment variant, the magnetrons 15 are only introduced through theupper openings 10 in the upper outer walls 7 of the system and thevacuum pumps 16 are (exclusively also) mounted directly on the covers11, which close the upper and lower openings 10, 23 in the upper 7 orlower outer walls 8. In order to adjust the pump power of this designembodiment to that according to FIG. 1, where two (in each side outerwall 9 one) vacuum pumps 16 are connected, two vacuum pumps 16 each arelocated in a row of pumps vertical to the direction of transportation13, which is not discernible in the selected figure as a result of thepumps arranged one after the other in the direction of view.Corresponding to the arrangement of the gas separation in the lowerpartial compartment 19, the suction openings 12 in this embodimentvariant, which lead to the adjoining coating compartments 3, are tightlyclosed in this section 21 with seals 14.

The even, horizontal elements 17 are located on angular shaped holders24, which are situated on the separating walls 4. A vertical element 20is attached onto the horizontal element 17 in the upper partialcompartment 18 approximately in the center by means of a joint 26, whichis fasted onto the upper cover 11 in its vertical position by means ofthe fixing elements 25. The horizontal element 17 in the lower partialcompartment 19 exhibits two suction openings 12 though which thetransportation plane 5 can be evacuated.

Elongate Vacuum System for Coating One or Both Sides of a Flat SubstrateREFERENCE SIGN LIST

-   -   1 Substrate    -   2 Evacuation compartments    -   3 Coating compartments    -   3 a,b,c First, second, third coating compartment    -   4 Separating wall    -   5 Transportation plane    -   6 Sluices    -   7 Upper outer wall    -   8 Lower outer Wall    -   9 Side outer wall    -   10 Upper opening    -   11 Cover    -   11 a Side cover    -   12 Suction opening    -   13 Direction of transportation    -   14 Closure    -   15 Magnetron    -   16 Vacuum pump or vacuum connection    -   17 Horizontal element    -   18 Upper partial compartment    -   19 Lower partial compartment    -   20 Vertical element    -   21 Section    -   22 Transport rollers    -   23 Lower opening    -   24 Holders    -   25 Fixing elements    -   26 Joint

1. Elongate vacuum system for coating one or both sides of a flatsubstrate which can be moved through the vacuum system in atransportation plane by means of a transport system, wherein the vacuumsystem comprises at least one magnetron with magnetron surrounding areaand is subdivided into successive compartments in a direction oftransportation of the substrate by separating walls having closeablesuction openings, which compartments can be evacuated either directlyvia a vacuum connection located on a compartment or indirectly via asuction opening in a separating wall, wherein at least one compartmentcomprises an upper partial compartment which is located above thesubstrate, said partial compartment comprising, in at least one of outerwalls thereof, a closeable upper opening, and wherein horizontal and/orvertical elements are mountable in the upper partial compartment forsubdivision of the upper partial compartment into several sections. 2.Elongate vacuum system according to claim 1, wherein at least a furtherlower compartment limited by the separating walls is located below thetransportation plane, said lower compartment having a closable loweropening in one of the outer walls as well as a closeable suction openingin each separating wall.
 3. Elongate vacuum system according to claim 2,wherein horizontal and/or vertical elements are mountable in the lowerpartial compartment for subdivision of the lower partial compartmentinto several sections.
 4. Elongate vacuum system according to claim 3,wherein the lower partial compartment exhibits a structure reflectedaround the transportation plane of the upper compartment opposite thelower partial compartment, above the transportation plane.
 5. Elongatevacuum system according to claim 2, wherein the upper and lower openingscan be closed with covers and at least one magnetron is mounted on acover of said covers and/or a vacuum connection is present.
 6. Elongatevacuum system according to claim 5, wherein the covers exhibit the samedimensions to one another.
 7. Elongate vacuum system according to claim2, wherein the upper and lower openings of all partial compartmentsexhibit the same dimensions.
 8. Elongate vacuum system according toclaim 2, wherein at least one of the upper or lower openings in a sideouter wall of an upper and/or lower partial compartment comprises avacuum connection.
 9. Elongate vacuum system according to claim 3,wherein the horizontal and/or vertical elements for subdivision of theupper and lower partial compartments are even.
 10. Elongate vacuumsystem according to claim 3, wherein at least one horizontal element ofa partial compartment can be placed on holders having a horizontalsupporting surface, which holders are present on at least two oppositewalls of the partial compartment.
 11. Elongate vacuum system accordingto claim 3, wherein a vertical element is fastened on at least onehorizontal element by means of a joint and the vertical element extendsbetween the horizontal element and the upper or lower outer wallsdirectly opposite the horizontal element.
 12. Elongate vacuum systemaccording to claim 3, wherein at least one horizontal element has aninsertion device for holding a vertical element and the vertical elementextends between the horizontal element and the upper or lower outerwalls directly opposite the horizontal element.
 13. Elongate vacuumsystem according to claim 11, wherein fixing elements are present on acover which closes the upper or lower opening located in the upper orlower outer wall opposite the horizontal element, which fixing elementsfix the vertical element in position after closure of the upper or loweropening.
 14. Elongate vacuum system according to claim 3, wherein in atleast one upper and/or lower respective partial compartment a horizontalelement is located in such a way that a section of the respectivepartial compartment is separated off from a space surrounding thetransportation plane.
 15. Elongate vacuum system according to claim 3,wherein the horizontal and/or vertical elements of at least one partialcompartment have a closeable additional suction opening.
 16. Elongatevacuum system according to claim 15, wherein size of the suctionopenings in the separating walls of the upper and/or lower partialcompartments and/or of the additional suction opening in the horizontaland/or vertical elements is adjustable.